The present invention relates to hand tools and, more particularly, to hand tools useful in carpentry. Even more particularly, the present invention relates to stud finders for locating magnetic fastening devices retaining building studs in place.
One of the problems faced by a person attempting to perform renovation of an existing structure is discerning the hidden elements of the structure. For example, when it is desired to affix something to a wall, it is frequently desirable to drive a screw or a nail into a wooden stud which forms the main structural supporting member of the wall. In most conventional construction, however, the locations of studs is hidden by overlying layers of, for example, plaster, sheetrock, wallpaper or paneling.
For many years, it has been conventional to locate studs based on the knowledge that studs are conventionally installed using steel nails. The locations of the steel nails are determined magnetically, and the locations of the studs are inferred from the nail locations.
One of the simplest magnetic devices, sold under the trademark Stud Finder, by Red Devil, Inc. of Union N.J., employs a magnet assembly containing a small bar magnet pivoted within a plastic housing. When the magnet assembly is brought within about one-half inch (1.23 centimeters) of a steel nail, one of the magnetic poles of the bar magnet is attracted to the steel in the nail, thereby rotating the magnet assembly. The Stud Finder is then moved until the magnet assembly is aligned at right angles to the wall. This marks the location of one nail, and of the stud into which it is drive. Once one stud is located, conventional regularity in spacing of studs, at 24 or 48 inches apart (corresponding to one-half, or the full width of a conventional four-foot panel), reduces the difficulty of finding other studs.
A conventional Stud Finder includes a metallic bar magnet enclosed within a two-piece plastic jacket. The plastic jacket is convenient, since each half includes a protuberance useful for pivoting within the housing. The plastic jacket is further useful since it can be given a suitable color.
It will be recognized by those skilled in the art that a three-piece magnet assembly (metallic bar magnet and two halves of the plastic jacket) add to the manufacturing and assembly time and cost. An alternative technique to reduce the manufacturing and assembly time and cost appears to be desirable.